Thermoelectric devices have already been proposed that use elements, called thermoelectric elements, that make it possible to generate an electric current in the presence of a temperature gradient between two of their opposing faces by the phenomenon known as Seebeck effect. These devices comprise a stack of first pipes, intended for the circulation of the exhaust gases from an engine, and second pipes, intended for the circulation of a heat-transfer fluid of a cooling circuit. The thermoelectric elements are sandwiched between the pipes so as to be subjected to a temperature gradient originating from the temperature difference between the hot exhaust gases and the cold coolant.
Such devices are of particular interest because they make it possible to produce electricity from a conversion of the heat originating from the engine exhaust gases. They thus offer the possibility of reducing the fuel consumption of the vehicle by replacing, at least partially, the alternator usually provided therein to generate electricity from a belt driven by the crankshaft of the engine.
One drawback of the known devices is that they require a very good contact to be assured between the thermoelectric elements and the pipes. It is thus necessary to have pipes that have a flatness and a surface finish that have an impact on the cost price of the device.
A first solution, consisting in reinforcing the contact by virtue of tie rods exerting a force on the stack of pipes, has been tested. This solution does, however, require the use of pipes that do risk being crushed on themselves under the effect of this force, resulting in an overconsumption of material.
The known thermoelectric elements are also fragile, in particular to the shear forces, and the thermal expansion of the pipes can damage them.